The Conservatives begin their conference this weekend at a moment when the political temperature is perceptibly rising. Labour has had a good week, albeit one in which Ed Miliband steered the party in a firmly Left-wing direction. The Tories remain behind in the polls, with Ukip a real threat in both next year’s European elections and in 2015. Many Tories continue to chafe at the frustrations of coalition: in his interview with this paper today, Conservative Party chairman Grant Shapps is open that he “hates” the arrangement. Meanwhile, Boris Johnson again hints at a return to the Commons. This, then, is a key moment for the Prime Minister to re-assert his authority and his vision for the party.

In truth, Mr Cameron can be pleased with his progress. The economy is finally starting to turn around — later than he and the Chancellor hoped but still in time for the next election. Whatever the annoyance of some Tories, the Coalition has proved far more durable than many initially predicted. What’s more, the Tories have been the clear winners: despite some concessions to the Liberal Democrats, the main contours of policy on the economy, public spending, welfare reform and education have been solidly Conservative. The Government is behind but this is mid-term, and Labour’s lead has looked shakier of late.

Still, Mr Cameron faces a formidable task in winning a majority in 2015: a fresh coalition is, on current polling, the more realistic outcome. Next week he must convince the party faithful — and his own MPs — that the party is still Conservative enough to win back voters defecting to Ukip. But he must also make the case for achieving Tory goals through coalition — something the public may perhaps be more open to than the critics in his own party.

The right rail links

Today's comments on HS2 by London transport boss Sir Peter Hendy ramp up the pressure on ministers trying to deliver the new high-speed London-Birmingham rail link. Sir Peter has amplified the Mayor’s case, saying it is a “bodge” for the plans not to include a full tunnelled link towards a possible Thames estuary airport. He also endorses the Mayor’s call for a new station at Old Oak Common to link to Crossrail, for more tunnelled sections in London to protect residents from noise, and for a Crossrail 2, from Euston to Wimbledon, for around 2030 when HS2 is extended north to Manchester.

All these ideas will cost more, at a point when concern over rising costs have put the scheme under new pressure: this week shadow chancellor Ed Balls gave his clearest hint yet that Labour may withdraw its support. But HS2’s appointment of the formidable Sir David Higgins as its new chairman, currently boss of Network Rail and before that of the Olympic Delivery Authority, is a powerful statement of intent. We need to get HS2 right if it does go ahead. A link to Crossrail is essential. But a link to an airport that even the Mayor concedes probably will not happen is much less important than Crossrail 2 — which an overloaded Tube will need before 2030. We have to plan boldly now for London’s future transport infrastructure.

Solid gold

The British Museum’s Beyond El Dorado exhibition, which opens next month, promises to be just as spectacular as recent blockbuster shows. As we report today, the pre-Columbus gold treasures were flown in from Bogotá under huge security. That is appropriate for such extraordinary treasures, going on show in one of London’s greatest treasures.